Marianne Lemoine / ctools

…ts the intervals, leading in the worst case to an empty event list if no overlap exists.

…odel with a standard diffuse cube background model that can be used for stacked analysis. The model container can be either retrieved using the models() method, or it can be written to disk with the save() method.

Conflicts:
	ChangeLog
	NEWS

As the GCTAObservation class now handles transparently the disposal and re-loading of information it is not needed anymore to re-load the event list upon call of the obs() method. We thus can put the obs() method inline as before.

The memory needs for ctobssim have been reduced by first working on a local copy of the CTA observation (this de-allocates properly and memory cache associated to the response functions), and by saving and disposing the event lists immediately if called using the execute() method (this is the method called when the tool is run from the command line).

…s. This method is useful for debugging the memory usage of ctools.

…d scave() methods to ctool interface. Add read_ahead() method to handle reading of task parameters at the beginning of the task execution. Remove all m_read_ahead members from the derived classes.

…esponse for all CTA observation in the container that have not yet a response using the task parameters.

…ss for CTA observation response setting.

…ovided by the base class

The ctool base class is now used in the ctbin tool. The get_ebounds() method has been moved to the ctool base class so that it can be used also in other tools. This reduces code duplication.